A Jersey City man has been sentenced to 15 years in prison for having his 4-year-old daughter perform oral sex on him and he must serve more than 12 years before being eligible for parole, officials said today.In February, the Arlington Avenue man who turns 28 tomorrow was found guilty of aggravated sexual assault and endangering the welfare of his daughter, who is now 8."The victim will be well over 18 by the time her father is released," said Hudson County Assistant Prosecutor John Mulkeen today of the sentence meted out by Hudson County Superior Court Judge Sheila Venable Friday. "It was a well investigated case by the Hudson County Prosecutor's Office's Special Victims Unit."The name of the convicted child molester is being withheld to protect the identity of the victim.The child was 6 years old on Aug. 21, 2009 when she told her baby-sitter what her father had made her do and the baby-sitter told the girl's mother the next day. The mother had not yet contacted police when an anonymous caller gave the information to the state Division of Youth and Family Services on Aug. 24, Mulkeen said.The mother, who was 28 years old at the time, was not prosecuted, but the victim and her younger sister were taken away by DYFS at that time. The mother testified for the prosecution at trial.The father was arrested on Aug. 25, 2009 and at the end of a recorded interview he asked a female officer to leave the room and tearfully "expressed guilt, felt bad, and admitted that he did it and gave even more details than the baby-sitter had," Mulkeen said.When the victim testified at trial she clearly identified her father as the one person that had touched her inappropriately, Mulkeen said. The father testified that he had been forced to make the incriminating statement, but the jury didn't buy it.After his arrest, the man posted bail on Sept. 15, 2009, but his bail was revoked when he was convicted on Feb. 16, 2011. He must register as a sex offender and undergo supervision for life.